Check the MTU of an interface on a Linux host.


Nagios and Icinga2 plugin to check the MTU of an interface on a Linux host and throw and alarm if the configured MTU deviates from the desired MTU.


This plugin requires:

  • Python3

How it works

The plugin reads the configured MTU from /sys/class/net//mtu. An alarm is raised if the configured MTU does not match the desired MTU.

Performance data

This plugin provides the following metrics:

  • mtu: configured MTU
  • desired_mtu: desired MTU


See the examples below or execute the plugin with -h/--help.


Just provide the configured MTU:

./check_linux_mtu -d eth0
CONFIGURED MTU OK - Configured value is 1500. | mtu=1500

Check that the configured MTU matches the desired MTU:

./check_linux_mtu -d eth0 --desired-mtu 9000
CONFIGURED MTU CRTITCAL - Configured value is 1500, while the desired value is 9000 | mtu=1500 desired_mtu=9000